Method and apparatus for adjusting armatures of electromagnetic



C. O. HARRINGTON. METHOD AND ABPARHUS FOR ADJUSTING ARMATURES 0EELECTROMAGNETIC DEVICES. APPLICATION FILED JAN. I7. I917.

1,308,585. Patented July 1,1919.

E] Y m wnuzsss mvzu-ron THE COLUMBIA PLANOGIAPH 60., WASHINGTON, D. 1:.

UNITED STATES PATENT OFFICE.

CLINTON O. HARRINGTON, OFEDGEVI'OOD BOROUGH, PENNSYLVANIA, ASSIGNOR TOTHE UNION SWITCH & SIGNAL COMPANY, OF. SWISSVALE, PENNSYLVANIA, A COR-PORATION OF PENNSYLVANIA.

METHOD AND APPARATUS FOR ADJUSTING ARMATURES OF ELECTROMAGNECIIIGDEVICES.

Specification of Letters Patent. I

Patented July 1, 1919.

Application filed January 17, 1917. Serial No. 142,818.

T 0 all whom it may concern.

Be it known that I, CLINTON O. HARRING- TON, a citizen of the UnitedStates, residing at Edgewood borough, in the county of Allegheny andState of Pennsylvania, have in vented certain new and usefulImprovements in Methods and Apparatus for Adjusting Armatures ofElectromagnetic Devices, of which the following is a specification. 1 1

This invention relates to electromagnets, and has for its object theprovision of a method and apparatus for adjusting the armature of anelectromagnet to give a predetermined torque to the armature when theeloctromagnet is supplied with a current of a predetermined potentialand the armature is in the closed position, whereby the properfunctioning of the armature will be insured.

Other objects of the invention will appear from a consideration of thefollowing de tailed description, taken inconnection with theaccompanying drawings forming a partof this specification, with theunderstanding, however, that the embodiment illustrated,

though practical, is by no means the onlyshowing of the drawings, butmay be changed and modified in various particulars within the scope ofthe appended claims.

In the drawings, Figure 1 is a view showing, in rear elevation, one formof electromagnet having applied thereto oneform of apparatus embodyingmy invention, such apparatus being diagrammatically shown in part. Fig.2 is a vertical sectional view taken on the line IIII of Fig. 1.

Similar reference characters refer to similar parts in each of theviews.

Referring to the drawings in detail, my invention as here shown isapplied to an electromagnetic device M, comprising two windings W and Wmounted on cores C and C respectively, the lower ends of the cores beingformed withenlarged portions F and F respectively, which constitute polepieces. The upper ends of the cores C and. C are reduced in diameter topass through holes in a back strap S, and are threaded to receive nuts10 and 10 respectively, where by the back strap S and the windings W andV are retained uponthe cores. The electromagnet also includes anarmature A mature A to be attracted to the pole pieces F, F, as will beunderstood. The movement of the armature A toward the pole pieces may belimited, so as to vary the closed position of the armature, by means ofa screw X, which passes through a threaded hole in a bridge bar 12. Thebar12 is formed of non-mag netic material, such as brass or the like,and as best seen in Fig. 1 connects the cores C and C at a point betweenthe windings W and W and the pole pieces F and F, the opposite ends ofthe bar being formed with suitable openings to receive the cores. Themedial portion of bar 12, adjacent its forward edge, is provided with athreaded opening to receive the screw.X, such screw having its lowerend. rounded for engagement with the armature A. Mounted upon'the screwat the underside of the bar 12 is a nut 13 which is designed to coactwith the bar to lock the screw in adjusted position, as will beunderstood. Y

From this construction, it is evident that by adjusting the screw Xvertically within the bar 12, the closed position of the armature A withrespect to the pole pieces F and F will be accordingly varied.

The screw X is then adjusted to a point which the operator thinks may beapproximately correct, and, while the armature A is held in contact withthe screw by hand or otherwise, the pole-changer P is suddenly reversedand the throw of the galvanometer needle is noted. If the throw isgreater than the proper value, the screw X is turned down to give alarger air gap between the armature and the pole-faces when the armatureis in contact with the screw; it the throw is less than the propervalue, the screw is turned'up to reduce this air gap. The process isrepeated until the galvanometer throw is the proper value upon reversalof the pole-changer, and when the proper adjustment of the screw issecured it is locked in such position by the nut 13. It will then beknown that when the electromagnet is energized at the proper currentvalue and the armature is in engagement with the screw X, the desiredtorque will be exerted on the armature. This desired torque can thus besecured irrespective of any irregularities in the magnetic circuit such,for example, as unevenness of the pole faces or of the armature, oradditional reluctance at the junction of the back strap with eithercore.

My invention is of particular advantage in connection withelectromagnetic relays wherein contacts are operated by the armature A.In such instance the pressure exerted on the contacts when the armatureis closed will bethe desired value regardless of irregularities in themagnetic circuit, provided the electromagnet is energized at thepredetermined current value. My invention is not, however, limited toelectromagnetic relays, but is applicable to any electromagnetregardless of the means' controlled or operated by the armature.

Having thus described my invention, what I claim is:

1. An apparatus of the character described, comprising an electromagnetincluding an armature, a source of current for said electromagnet, meansfor varying the flow of said current as supplied to said electro magnet,means for determining the magnetic flux in the magnetic circuit of theelectromagnet, and means for adjusting the closed position of saidarmature.

2. An apparatus of the character described, comprising an electromagnetincluding an armature, a source of current -tor said electromagnet, meanfor determining the magnetic flux in said armature, and means foradjusting said armature to cause the armature to carry a predeterminedflux at a given energization of the electromagnet when the armature isin closed position.

3. The method of adjusting an armature with relation to an elcetromagnetso that when the armature is in. the closed position a givenenergization of the magnet will cause a predetermined pull on thearmature, which consists in supplying a given current to the magnet,measuring the magnetic flux produced thereby in the armature, andadjusting the closed position of the armature to such location that theflux in the armature has a predetermined value.

4. The method of adjusting an lli'lllltlll'G with relation to anelectromagnet so that when the armature is in the closed position agiven energization of the magnet will cause a predetermined pull on thearmature, which consists in supplying a given current to the magnet,measuring the magnetic flux pro duced thereby in the magnetic circuit,and adjusting the closed position of the armature to such location thatthe flux in said magnetic circuit has a predetermined value.

Intestimony whereof I aiiix my signature in presence of two witnesses.

CLINTON O. HARRINGTON.

Vitnesses A. HERMAN IVEGNER, EDWIN D. IAMS.

Copies of this patent may be obtained for five cents each, by addressingthe Commissioner of Patents. Washington, D. C.

